It is proposed that one of the ways in which individuals experience crowding is through a two-step process involving physiological arousal (violations of personal space) and attributions about the cause of arousal. The research is aimed at supporting the theory and consequently demonstrating means by which the experience of crowding can be reduced without increasing physical space. A second aim is to increase general understanding of the attribution process by identifying variables that influence the direction of attributions to explain arousal. One set of studies examines social and environmental conditions that determine the amount of personal space an individual requires. These variables include area size, individual's previous environment, and degree of social deindividuation involved in the interaction. A second set of studies examines how stimulus properties influence attributions. Such dimensions as novelty, salience, threat potential, and arousal will be studied. Identifying the role of each of these variables will not only explicate the attribution process but also suggest how high density environments can be managed to reduce crowding and associated negative effects. The use of physiological measures will indicate the relationship between stress and crowding. A final set of studies examines how individuals in natural environments (prison units) construct their living areas to reduce crowding.